The present invention relates to a battery charge monitoring device for monitoring the operation of charging a battery which is mounted on a vehicle, for example, electric vehicle or hybrid vehicle.
In, for example, automobile industries in recent years, an electric vehicle which travels by utilizing only electricity as energy, and a hybrid vehicle on which both an engine and an electric motor are mounted, have been put into practical use from the viewpoints of the reduction of the emission of carbon dioxide and the efficient utilization of energy. In the general hybrid vehicle, when the vehicle decelerates, kinetic energy is converted into electric energy, which is recovered and with which a battery is charged, and when the vehicle travels, the consumption of fuel such as gasoline is suppressed by utilizing the recovered electric energy. However, merely by recovering the kinetic energy during the deceleration, the effect of suppressing the consumption of the fuel is low, and also the effect of reducing the carbon dioxide is low.
In this regard, a plug-in hybrid vehicle (plug-in HV) has been developed in order to heighten the effect of reducing the carbon dioxide. The plug-in hybrid vehicle has a function in which a plug disposed on an automobile side is inserted into a power source consent for domestic use, or the like, thereby to charge the battery of the automobile side from a domestic power source (commercial AC power source: AC 100V, or the like). Accordingly, electric energy obtained by the charge from the domestic power source can be utilized for the travel of the automobile, in addition to the kinetic energy recoverable during the deceleration. It therefore becomes possible to suppress the consumption of the fuel by raising the frequency in use of the electric motor and to heighten the effect of reducing the carbon dioxide by using the electric motor of high efficiency at a high frequency in use.
On the other hand, supposing a case where such plug-in hybrid vehicles have generally spread in the future, the act of robbery of electric power (the robbery of electricity) might be performed. More specifically, the plug-in hybrid vehicle can charge its battery by inserting the plug into a public power source installation, the power source consent of the house of the owner of the vehicle, the power source consent of another's house, or the like in any place where the consent of the power source exists. Therefore, it is also considered that the owner or the like of the plug-in hybrid vehicle might illegally perform the battery charge (the robbery of electricity) without leave, without being permitted by the rightful person of the power source installation or without paying a fee to the rightful person.
Techniques disclosed in, for example, Patent Document 1, Patent Document 2 and Patent Document 3 have been known as prior-art techniques for preventing the illegal charge, etc. which proceed in the outdoors or the like.
In Patent Document 1, there is disclosed the technique for feeding a portable equipment with electric power from a small-sized motor-driven vehicle on which a small-sized battery is mounted as in, for example, a motor-driven wheelchair.
Patent Document 2 discloses the technique for centrally managing processes for charging the batteries of individual electric vehicles which are parking in a multilevel parking area.
Patent Document 3 discloses the technique for preventing the act of tearing off the covering of a power feed cable and then connecting a load from outside so as to rob electricity. Concretely, it proposes to monitor a voltage fluctuation and to detect the occurrence of an abnormality such as the robbery of the electricity, in a case where an abnormal voltage drop has been observed for a long term.
[Patent Document 1] U.S. Pat. No. 6,762,572B1 (JP-A-2001-157301)
[Patent Document 2] JP-A-2001-359203
[Patent Document 3] JP-A-2003-21649
When the technique disclosed in Patent Document 3 is adopted by way of example, the existence or nonexistence of the electricity robbery can be detected by monitoring the abnormal drop of a power source voltage for the long term. However, assuming, for example, a case where the battery of the plug-in hybrid vehicle is charged from the power source consent, a charging time period for one charge is limited to only a comparatively short time period on the order of several hours. Therefore, unless the acts of the illegal battery charges are repeated many times for the long term, the existence or nonexistence of the illegal battery charge cannot be detected with the technique of Patent Document 3. That is, in a case where, while driving and moving the plug-in hybrid vehicle, a specified criminal has conducted the act of illegally charging the battery of the plug-in hybrid vehicle from those power source consents of various movement sites which differ from one another, the act of the electricity robbery cannot be sensed.